Hi, I am currently working with TN visa which expires on Dec 2017. I got selected in the H1B 2018 lottery and the application has a status of received. I am planning to go outside USA in the following months, July and October.

My question here are, It is possible to travel abroad with my current TN visa?
It will be a problem if my H1B got approved in that period while I am outside USA?
Co-workers from India are saying that I cannot leave the country until the H1B process ends, it is that true?